Site index, boniteet in Estonian, is the productivity class of a forest site: it shows how well trees grow there. Estonia uses six classes, from the most productive IA down to the poorest V. The class is set from stand height at a reference age: same species, same age, taller stand means a better site index.
In forest land valuation it is the single input almost everything else depends on. The reason is in the table below.
Site index sets rotation age
The Estonian Forest Act ties minimum clearcut age to species and site index. The same species reaches cutting maturity sooner on a good site than a poor one.
| Species | IA | I | II | III | IV | V |
|---|---|---|---|---|---|---|
| Scots pine | 90 | 90 | 90 | 100 | 110 | 120 |
| Norway spruce | 80 | 80 | 80 | 90 | 90 | 90 |
| Birch | 60 | 60 | 70 | 70 | 70 | 70 |
| Aspen | 30 | 40 | 40 | 50 | 50 | 50 |
| Alder | 60 | 60 | 60 | 60 | 60 | 60 |
| Oak and hardwoods | 90 | 90 | 100 | 110 | 120 | 130 |
For Scots pine the spread is thirty years: 90 on site index IA, 120 on V. For aspen the relative spread is larger still, 30 years against 50.
In a discounted cash flow that is not a small detail. Harvest revenue arriving thirty years later is worth roughly four times less in present value at a 5% real discount rate. Two otherwise identical parcels differing only in site index are nowhere near the same value.
What site index measures in practice: increment
Site index is the classification; increment is what the classification measures. Estonian stands averaged 7.2 cubic metres per hectare per year of volume increment in 2025, on an average standing reserve of 215 cubic metres per hectare (Statistics Estonia, table KK51).
Data table
| Area | Change |
|---|---|
| Aspen | 9.7 m³/ha |
| Spruce | 9.3 m³/ha |
| Common alder | 7.8 m³/ha |
| Grey alder | 6.6 m³/ha |
| Birch | 6.5 m³/ha |
| Pine | 6.3 m³/ha |
The species spread is clear. Aspen grows fastest at 9.7 m³/ha per year, Pine slowest at 6.3. That does not make an aspen stand a better buy than a pine stand: fast growth and high timber value are different things, and pine carries the highest standing reserve per hectare.
The national average has been falling
The trend is worth noting. Standing reserve per hectare has fallen from 225 to 215 cubic metres, and increment from 7.6 to 7.2, in five years.
Data table
| Period | Reserve, m³/ha |
|---|---|
| 2015 | 229 |
| 2016 | 229 |
| 2017 | 229 |
| 2018 | 227 |
| 2019 | 226 |
| 2020 | 225 |
| 2021 | 222 |
| 2022 | 219 |
| 2023 | 217 |
| 2024 | 216 |
| 2025 | 215 |
Part of that follows from harvesting: cutting mature stands lowers the average and younger forest grows differently. For a buyer the conclusion is practical. The national average of 215 m³/ha anchors no specific parcel, and it is drifting down.
Frequently asked questions
What is boniteet?
Boniteet is the Estonian term for forest site index: the productivity class of a forest site, from IA (most productive) through I, II, III, IV to V (least). It is determined from stand height at a reference age, so for the same species and age a taller stand means a better class.
Why does site index matter for forest land value?
Because it sets rotation age. Estonian law ties minimum clearcut age to species and site index, so the same species reaches maturity sooner on a good site. For Scots pine that is 90 years on IA against 120 on V. Revenue arriving thirty years later is worth roughly four times less at a 5% real discount rate.
How many site index classes are there in Estonia?
Six: IA, I, II, III, IV and V, from most to least productive.
What is the average volume increment of Estonian forest?
About 7.2 cubic metres per hectare per year across all stands, on an average standing reserve of roughly 215 cubic metres per hectare (Statistics Estonia, table KK51). Both have drifted down over the last five years.
Which tree species grows fastest in Estonia?
By annual volume increment, aspen and spruce lead at around 9 to 10 cubic metres per hectare per year, against roughly 6 for pine. Fast growth and high timber value are not the same thing, and pine carries the highest standing reserve per hectare.
Where can I find a parcel's site index?
In the Estonian forest register, recorded per stand alongside species and age. It is a measured attribute rather than an estimate, and it is the first thing to check on a parcel.
How to check it
Site index is recorded per stand in the Estonian forest register. It is a measured attribute rather than an estimate, and it is the first thing to look at on a parcel.
The EMPI methodology takes site index and species from the forest register and uses them to set rotation age rather than applying a generic curve. A blanket 80- or 90-year rotation overstates the harvest wait for fast-growing species by a wide margin. The forest valuation walkthrough covers how that becomes a cash flow.
Where a parcel's site index is unknown, valuation is only possible on an assumption. That assumption should then be stated, not buried in a price.